Alberto Carmagnini

PhD student

Profile

Summary: The domestication of plants and animals had a dramatic influence on human history by promoting the transition from a nomadic to sedentary. The agricultural revolution significantly altered the landscape around human settlements creating different ecological niches which induced different selective pressure on some species and promoted their domestication. Over millennia of artificial selection, following animal domestication, humans have explored the phenotypic landscape of domestic species very rapidly to differentiate them from their wild progenitors.

Our understanding of the process of domestication, however, is still rudimentary. Compelling evidence of gene flow between wild and domestic lineages have been reported suggesting that animal domestication has been a reticulate process analogous to parapatric speciation characterised by a population bottleneck followed by an expansion. Gene-flow is particularly interesting given that it is expected to reduce the phenotypic differentiation between populations. On the other hand, introgression also represents a potential source of new variants that can become beneficial in a new environment or simply provide standing genetic variation for selection to act on. Population bottlenecks instead have the opposite effects: they reduce diversity and can lead to relaxed selection. Random genetic drift could therefore have increased the frequency of rare, previously deleterious, variants. If these variations were mostly recessive this might have increased additive genetic variance in domestic taxa, which could have accelerated the exploration of phenotypic landscape through artificial selection. As such, bottlenecks may have been primordial for the rapid morphological differentiation between wild and domestic populations.

My project aims to address these questions using genomics and geometric morphometrics.